OVMS3-idf/components/xtensa/expression_with_stack_xtensa_asm.S

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// Copyright 2015-2019 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <freertos/xtensa_context.h>
.extern esp_clear_watchpoint
.text
/**
* extern void switch_stack_enter(portSTACK_TYPE *stack, portSTACK_TYPE *backup_stack);
*/
.globl esp_switch_stack_enter
.type esp_switch_stack_enter,@function
.align 4
esp_switch_stack_enter:
#ifndef __XTENSA_CALL0_ABI__
entry sp, 0x10
mov a4, a1
s32i a4, a3, 0 /* on a3 there is a safe place to save the current stack */
l32i a4, a2, 0 /* obtains the user allocated stack buffer */
mov a1, a4 /* sp register now contains caller specified stack */
retw
#else
#error "this code is written for Window ABI"
#endif
/**
* extern void switch_stack_exit(portSTACK_TYPE *backup_stack);
*/
.globl esp_switch_stack_exit
.type esp_switch_stack_exit,@function
.align 4
esp_switch_stack_exit:
#ifndef __XTENSA_CALL0_ABI__
entry sp, 0x10
movi a6, 2
movi a4, esp_clear_watchpoint
callx4 a4 /* clear the watchpoint before releasing stack */
l32i a4, a2, 0 /* recover the original task stack */
mov a1, a4 /* put it on sp register again */
retw
#else
#error "this code is written for Window ABI"
#endif